Tentpole: An expensive, heavily promoted movie that its studio hopes will make a killing on its wide-release opening weekend and generate or extend a lucrative franchise.

Sleeper: A low-budget film that strikes a chord with audiences, exceeds box-office expectations and makes fools of the folks who spent zillions making tentpoles.

Four movies opened this weekend, three of them tentpoles. R.I.P.D., a comic-book action fantasy starring Jeff Bridges and Ryan Reynolds, mixed the themes of Ghostbusters and Men in Black: dead cops come back to Earth to battle evil spirits. Red 2, sequel to the 2010 hit, reconvened Bruce Willis and his elite team of CIA alter kockers. And the DreamWorks animated feature Turbo, about a speedy snail (voiced by Reynolds) who wants to race in the Indy 500, borrowed from the Pixar movies Ratatouille and Cars — and from the old snail joke, “Look at that S car go!” The budgets for this new trio totaled about $400 million, plus another hefty bundle for marketing them.

Then a little haunted-house film crept in, swung its scythe and cut down those pricey tentpoles. Produced for just $20 million, The Conjuring won the weekend at North American theaters, according to preliminary studio estimates, by earning a sensational $41.5 million — more than any two of the other new pictures. The total for the weekend box office was about 20% below the same frame last year, when only one big movie opened; but that movie was The Dark Knight Rises, which earned $160.9 million for the fourth best opening ever, despite the tragedy of the Aurora, Colo., screening at which a dozen people were killed and 70 injured. This weekend was far calmer, and the crowds smaller, especially for every movie but The Conjuring. This Sunday’s sermon: Forget the tentpoles and stick with movie basics. A little, screaming child shall lead them.

Set in the 1970s, The Conjuring summons the spirits of two of that decade’s primal thrillers, The Amityville Horror and The Exorcist, with a based-on-a-true-story tale about the exploits of paranormal researchers Ed and Lorraine Warren (Patrick Wilson and Vera Farmiga) investigating the Rhode Island home a family has just moved into. This scare-athon from Saw director James Wan rode a wave of Internet interest and enthusiastic reviews (85% on Rotten Tomatoes) to the second highest opening for a low-budget R-rated horror movie, after the $52.6 million for Paranormal Activity 3 in 2011. The audience, which was 53% female and 59% over the age of 25, gave it an A-minus CinemaScore rating, unusually high for the genre. So this could be the rare horror film that doesn’t grab most of its money on the first weekend, as PA3 and The Purge did. The Conjuring might haunt multiplexes for the rest of the summer.And, with the movie’s high-fright quotient, no one will be sleeping through this sleeper.

The success of The Conjuring left its big-budget rivals stumbling blind, with little hope of making a profit and no question to ask but “Who greenlit this movie?” Red 2 cost about $84 million to produce, or 50% more than its predecessor, and grossed less on its opening weekend — $18.5 million to the original’s $21.8 million — a strong clue that, for Red’s audience, once was enough. The sequel, featuring such veterans as Helen Mirren and John Malkovich, attracted viewers about the age of its stars: 67% of the early visitors were older than 35, which in moviegoing terms is somewhere between geriatric and terminal. This audience gave the movie an O.K. B-plus rating on CinemaScore; but, for the film to break even, the grades will have to be much higher in foreign markets, where the first Red earned 55% of its global gross.

The advertising for Turbo tried to make young customers and their moms think it was a Disney or Pixar cartoon, yet the early audience response to this $135-million production was benign indifference. Those who went liked the movie (an “A” CinemaScore), but not nearly enough showed up. The $21.5 million Turbo managed marks the lowest opening for a DreamWorks animated feature since the Aardman co-production Flushed Away in 2006. Indeed, in its first weekend it finished behind Despicable Me 2, which in its third weekend earned $25.1 million. DM2 has now topped Pixar’s Monsters University as the summer’s animated champion, with a 19-day domestic take of $276.2 million (to $249 million for Monsters U.) and $584.6 million worldwide (to M.U.‘s $531.9 million). That must bring smiles to the movie bosses at Universal, which had another summer hit with Furious 6 ($712.5 million worldwide) and can almost afford to shrug off the weekend debacle that was R.I.P.D.

Or, as one industry wag renamed it, R.I.P.D.O.A. With a budget of between $130 million and $180 million (depending on whether you deduct the income for product placement, like for that Fresca bottle early in the film), this supernatural buddy-cop movie earned a post-mortem $12.8 million over the weekend and a fatal C-plus CinemaScore. R.I.P.D. joins the summer’s list of expensive flops that already includes After Earth, White House Down, The Lone Ranger and Pacific Rim — each of which earned two to three times as much its opening weekend as did this very bad movie.

In indie action, the mom-com Girl Most Likely opened in 353 theaters to a dismal $736,000 (a $2,085 per-screen average); the star, Kristen Wiig, will quickly expunge this effort from her résumé. Only God Forgives, the Thailand-set crime movie that reunited Ryan Gosling with his Drive director Nicolas Winding Refn, picked up a pallid $315,000 in 78 venues.

The one promising debut was that of The Act of Killing, whose directors convinced Indonesian thugs who had committed state-sponsored murders to reenact their crimes in the style of their favorite violent movies. Opening in one Manhattan theater to an impressive $28,100, this documentary provided chills beyond that of the blood spilled by The Conjuring’s vengeful witch — or the red ink that will engulf R.I.P.D.